class_docstr: A strategy with automatic trailing stop-loss, trailing the current
  price at distance of some multiple of average true range (ATR). Call
  `TrailingStrategy.set_trailing_sl()` to set said multiple
  (`6` by default). See [tutorials] for usage examples.
  
  [tutorials]: index.html#tutorials
  
  Remember to call `super().init()` and `super().next()` in your
  overridden methods.
code: def next(self):
      super().next()
      # Can't use index=-1 because self.__atr is not an Indicator type
      index = len(self.data) - 1
      for trade in self.trades:
          if trade.is_long:
              trade.sl = max(
                  trade.sl or -np.inf,
                  self.data.Close[index]
                  - self.__atr[index] * self.__n_atr,
              )
          else:
              trade.sl = min(
                  trade.sl or np.inf,
                  self.data.Close[index]
                  + self.__atr[index] * self.__n_atr,
              )
  
imports: from collections import OrderedDict
  from inspect import currentframe
  from itertools import compress
  from numbers import Number
  from typing import Callable, Optional, Sequence, Union
  import numpy
  import pandas
  from ._plotting import plot_heatmaps
  from ._stats import compute_stats
  from ._util import _Array, _as_str
  from .backtesting import Strategy
label_desc: Use image node_id 4 for calling the TrailingStrategy obj's underlying member method code with example usage: obj.next() without return types